fs/nilfs2/btnode.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * btnode.c - NILFS B-tree node cache
   4  *
   5  * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation.
   6  *
   7  * Originally written by Seiji Kihara.
   8  * Fully revised by Ryusuke Konishi for stabilization and simplification.
   9  *
  10  */
  11
  12 #include <linux/types.h>
  13 #include <linux/buffer_head.h>
  14 #include <linux/mm.h>
  15 #include <linux/backing-dev.h>
  16 #include <linux/gfp.h>
  17 #include "nilfs.h"
  18 #include "mdt.h"
  19 #include "dat.h"
  20 #include "page.h"
  21 #include "btnode.h"
  22
  23
  24 /**
  25  * nilfs_init_btnc_inode - initialize B-tree node cache inode
  26  * @btnc_inode: inode to be initialized
  27  *
  28  * nilfs_init_btnc_inode() sets up an inode for B-tree node cache.
  29  */
  30 void nilfs_init_btnc_inode(struct inode *btnc_inode)
  31 {
  32         struct nilfs_inode_info *ii = NILFS_I(btnc_inode);
  33
  34         btnc_inode->i_mode = S_IFREG;
  35         ii->i_flags = 0;
  36         memset(&ii->i_bmap_data, 0, sizeof(struct nilfs_bmap));
  37         mapping_set_gfp_mask(btnc_inode->i_mapping, GFP_NOFS);
  38 }
  39
  40 void nilfs_btnode_cache_clear(struct address_space *btnc)
  41 {
  42         invalidate_mapping_pages(btnc, 0, -1);
  43         truncate_inode_pages(btnc, 0);
  44 }
  45
  46 struct buffer_head *
  47 nilfs_btnode_create_block(struct address_space *btnc, __u64 blocknr)
  48 {
  49         struct inode *inode = btnc->host;
  50         struct buffer_head *bh;
  51
  52         bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
  53         if (unlikely(!bh))
  54                 return NULL;
  55
  56         if (unlikely(buffer_mapped(bh) || buffer_uptodate(bh) ||
  57                      buffer_dirty(bh))) {
  58                 brelse(bh);
  59                 BUG();
  60         }
  61         memset(bh->b_data, 0, i_blocksize(inode));
  62         bh->b_bdev = inode->i_sb->s_bdev;
  63         bh->b_blocknr = blocknr;
  64         set_buffer_mapped(bh);
  65         set_buffer_uptodate(bh);
  66
  67         unlock_page(bh->b_page);
  68         put_page(bh->b_page);
  69         return bh;
  70 }
  71
  72 int nilfs_btnode_submit_block(struct address_space *btnc, __u64 blocknr,
  73                               sector_t pblocknr, int mode, int mode_flags,
  74                               struct buffer_head **pbh, sector_t *submit_ptr)
  75 {
  76         struct buffer_head *bh;
  77         struct inode *inode = btnc->host;
  78         struct page *page;
  79         int err;
  80
  81         bh = nilfs_grab_buffer(inode, btnc, blocknr, BIT(BH_NILFS_Node));
  82         if (unlikely(!bh))
  83                 return -ENOMEM;
  84
  85         err = -EEXIST; /* internal code */
  86         page = bh->b_page;
  87
  88         if (buffer_uptodate(bh) || buffer_dirty(bh))
  89                 goto found;
  90
  91         if (pblocknr == 0) {
  92                 pblocknr = blocknr;
  93                 if (inode->i_ino != NILFS_DAT_INO) {
  94                         struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
  95
  96                         /* blocknr is a virtual block number */
  97                         err = nilfs_dat_translate(nilfs->ns_dat, blocknr,
  98                                                   &pblocknr);
  99                         if (unlikely(err)) {
 100                                 brelse(bh);
 101                                 goto out_locked;
 102                         }
 103                 }
 104         }
 105
 106         if (mode_flags & REQ_RAHEAD) {
 107                 if (pblocknr != *submit_ptr + 1 || !trylock_buffer(bh)) {
 108                         err = -EBUSY; /* internal code */
 109                         brelse(bh);
 110                         goto out_locked;
 111                 }
 112         } else { /* mode == READ */
 113                 lock_buffer(bh);
 114         }
 115         if (buffer_uptodate(bh)) {
 116                 unlock_buffer(bh);
 117                 err = -EEXIST; /* internal code */
 118                 goto found;
 119         }
 120         set_buffer_mapped(bh);
 121         bh->b_bdev = inode->i_sb->s_bdev;
 122         bh->b_blocknr = pblocknr; /* set block address for read */
 123         bh->b_end_io = end_buffer_read_sync;
 124         get_bh(bh);
 125         submit_bh(mode, mode_flags, bh);
 126         bh->b_blocknr = blocknr; /* set back to the given block address */
 127         *submit_ptr = pblocknr;
 128         err = 0;
 129 found:
 130         *pbh = bh;
 131
 132 out_locked:
 133         unlock_page(page);
 134         put_page(page);
 135         return err;
 136 }
 137
 138 /**
 139  * nilfs_btnode_delete - delete B-tree node buffer
 140  * @bh: buffer to be deleted
 141  *
 142  * nilfs_btnode_delete() invalidates the specified buffer and delete the page
 143  * including the buffer if the page gets unbusy.
 144  */
 145 void nilfs_btnode_delete(struct buffer_head *bh)
 146 {
 147         struct address_space *mapping;
 148         struct page *page = bh->b_page;
 149         pgoff_t index = page_index(page);
 150         int still_dirty;
 151
 152         get_page(page);
 153         lock_page(page);
 154         wait_on_page_writeback(page);
 155
 156         nilfs_forget_buffer(bh);
 157         still_dirty = PageDirty(page);
 158         mapping = page->mapping;
 159         unlock_page(page);
 160         put_page(page);
 161
 162         if (!still_dirty && mapping)
 163                 invalidate_inode_pages2_range(mapping, index, index);
 164 }
 165
 166 /**
 167  * nilfs_btnode_prepare_change_key
 168  *  prepare to move contents of the block for old key to one of new key.
 169  *  the old buffer will not be removed, but might be reused for new buffer.
 170  *  it might return -ENOMEM because of memory allocation errors,
 171  *  and might return -EIO because of disk read errors.
 172  */
 173 int nilfs_btnode_prepare_change_key(struct address_space *btnc,
 174                                     struct nilfs_btnode_chkey_ctxt *ctxt)
 175 {
 176         struct buffer_head *obh, *nbh;
 177         struct inode *inode = btnc->host;
 178         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
 179         int err;
 180
 181         if (oldkey == newkey)
 182                 return 0;
 183
 184         obh = ctxt->bh;
 185         ctxt->newbh = NULL;
 186
 187         if (inode->i_blkbits == PAGE_SHIFT) {
 188                 lock_page(obh->b_page);
 189                 /*
 190                  * We cannot call radix_tree_preload for the kernels older
 191                  * than 2.6.23, because it is not exported for modules.
 192                  */
 193 retry:
 194                 err = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
 195                 if (err)
 196                         goto failed_unlock;
 197                 /* BUG_ON(oldkey != obh->b_page->index); */
 198                 if (unlikely(oldkey != obh->b_page->index))
 199                         NILFS_PAGE_BUG(obh->b_page,
 200                                        "invalid oldkey %lld (newkey=%lld)",
 201                                        (unsigned long long)oldkey,
 202                                        (unsigned long long)newkey);
 203
 204                 xa_lock_irq(&btnc->i_pages);
 205                 err = radix_tree_insert(&btnc->i_pages, newkey, obh->b_page);
 206                 xa_unlock_irq(&btnc->i_pages);
 207                 /*
 208                  * Note: page->index will not change to newkey until
 209                  * nilfs_btnode_commit_change_key() will be called.
 210                  * To protect the page in intermediate state, the page lock
 211                  * is held.
 212                  */
 213                 radix_tree_preload_end();
 214                 if (!err)
 215                         return 0;
 216                 else if (err != -EEXIST)
 217                         goto failed_unlock;
 218
 219                 err = invalidate_inode_pages2_range(btnc, newkey, newkey);
 220                 if (!err)
 221                         goto retry;
 222                 /* fallback to copy mode */
 223                 unlock_page(obh->b_page);
 224         }
 225
 226         nbh = nilfs_btnode_create_block(btnc, newkey);
 227         if (!nbh)
 228                 return -ENOMEM;
 229
 230         BUG_ON(nbh == obh);
 231         ctxt->newbh = nbh;
 232         return 0;
 233
 234  failed_unlock:
 235         unlock_page(obh->b_page);
 236         return err;
 237 }
 238
 239 /**
 240  * nilfs_btnode_commit_change_key
 241  *  commit the change_key operation prepared by prepare_change_key().
 242  */
 243 void nilfs_btnode_commit_change_key(struct address_space *btnc,
 244                                     struct nilfs_btnode_chkey_ctxt *ctxt)
 245 {
 246         struct buffer_head *obh = ctxt->bh, *nbh = ctxt->newbh;
 247         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
 248         struct page *opage;
 249
 250         if (oldkey == newkey)
 251                 return;
 252
 253         if (nbh == NULL) {      /* blocksize == pagesize */
 254                 opage = obh->b_page;
 255                 if (unlikely(oldkey != opage->index))
 256                         NILFS_PAGE_BUG(opage,
 257                                        "invalid oldkey %lld (newkey=%lld)",
 258                                        (unsigned long long)oldkey,
 259                                        (unsigned long long)newkey);
 260                 mark_buffer_dirty(obh);
 261
 262                 xa_lock_irq(&btnc->i_pages);
 263                 radix_tree_delete(&btnc->i_pages, oldkey);
 264                 radix_tree_tag_set(&btnc->i_pages, newkey,
 265                                    PAGECACHE_TAG_DIRTY);
 266                 xa_unlock_irq(&btnc->i_pages);
 267
 268                 opage->index = obh->b_blocknr = newkey;
 269                 unlock_page(opage);
 270         } else {
 271                 nilfs_copy_buffer(nbh, obh);
 272                 mark_buffer_dirty(nbh);
 273
 274                 nbh->b_blocknr = newkey;
 275                 ctxt->bh = nbh;
 276                 nilfs_btnode_delete(obh); /* will decrement bh->b_count */
 277         }
 278 }
 279
 280 /**
 281  * nilfs_btnode_abort_change_key
 282  *  abort the change_key operation prepared by prepare_change_key().
 283  */
 284 void nilfs_btnode_abort_change_key(struct address_space *btnc,
 285                                    struct nilfs_btnode_chkey_ctxt *ctxt)
 286 {
 287         struct buffer_head *nbh = ctxt->newbh;
 288         __u64 oldkey = ctxt->oldkey, newkey = ctxt->newkey;
 289
 290         if (oldkey == newkey)
 291                 return;
 292
 293         if (nbh == NULL) {      /* blocksize == pagesize */
 294                 xa_lock_irq(&btnc->i_pages);
 295                 radix_tree_delete(&btnc->i_pages, newkey);
 296                 xa_unlock_irq(&btnc->i_pages);
 297                 unlock_page(ctxt->bh->b_page);
 298         } else
 299                 brelse(nbh);
 300 }